Semiconductor devices and methods of manufacturing semiconductor devices

ABSTRACT

A semiconductor device includes a substrate having an active region, a gate structure disposed on the active region, a source/drain region disposed in the active region at a side of the gate structure, a first interlayer insulating layer and a second interlayer insulating layer sequentially disposed on the gate structure and the source/drain region, a first contact plug connected to the source/drain region through the first interlayer insulating layer, a second contact plug connected to the gate structure through the first interlayer insulating layer and the second interlayer insulating layer, a first metal line disposed on the second interlayer insulating layer, and having a metal via disposed in the second interlayer insulating layer and connected to the first contact plug, and a second metal line disposed on the second interlayer insulating layer, and directly connected to the second contact plug.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.16/508,555 filed on Jul. 11, 2019, which is a continuation of U.S.application Ser. No. 15/493,965, filed on Apr. 21, 2017, now U.S. Pat.No. 10,396,034, issued Aug. 27, 2019, which claims priority under 35U.S.C. § 119 to Korean Patent Application No. 10-2016-0128352, filed onOct. 5, 2016 in the Korean Intellectual Property Office, the disclosuresof which are incorporated by reference herein in their entirety.

TECHNICAL FIELD

The present disclosure relates to semiconductor devices and methods ofmanufacturing the same.

DISCUSSION OF RELATED ART

As demands for high performance, high speed, and/or multifunctioning ofsemiconductor devices increase, the integration degree of semiconductordevices becomes higher. When semiconductor devices having micropatternswith a high degree of integration are manufactured, the implementationof micropatterns having a microwidth or a microdistance is required.Also, to overcome the limitations of planar metal-oxide-semiconductorfield-effect transistors (MOSFETs), semiconductor devices including finfield effect transistors (FinFETs), with a channel having athree-dimensional structure, have been developed.

When the size of semiconductor devices is reduced to meet therequirement of the FinFETs, an interval between contact plugs thereofmay decrease, and thus short circuits between the contact plugs mayoccur. In addition, metal vias connecting metal lines to contact plugsmay cause contact defects such as via open.

SUMMARY

Example embodiments of the present disclosure provide a semiconductordevice that may be scaled down, while preventing short circuits betweencontact plugs, and a method of manufacturing the semiconductor device.

According to an example embodiment of the present disclosure, asemiconductor device may include: a substrate having an active region; agate structure disposed on the active region; a source/drain regiondisposed in the active region at a side of the gate structure; a firstinterlayer insulating layer and a second interlayer insulating layersequentially disposed on the gate structure and the source/drain region;a first contact plug connected to the source/drain region through thefirst interlayer insulating layer; a second contact plug connected tothe gate structure through the first interlayer insulating layer and thesecond interlayer insulating layer; a first metal line disposed on thesecond interlayer insulating layer, and having a metal via disposed inthe second interlayer insulating layer and connected to the firstcontact plug; and a second metal line disposed on the second interlayerinsulating layer, and directly connected to the second contact plug.

According to an example embodiment of the present disclosure, asemiconductor device may include: a substrate; a gate structure disposedon the substrate; a source/drain region disposed at a side of the gatestructure; a first contact plug connected to the source/drain region,and formed in a substantially vertical direction from an upper surfaceof the substrate; a second contact plug connected to the gate structure,and formed in a substantially vertical direction from the upper surfaceof the substrate; and a first metal line and a second metal lineconnected to the first contact plug and the second contact plug,respectively, and disposed on a first level. An upper surface of one ofthe first contact plug and the second contact plug may be disposed onthe first level and directly connected to one of the first metal lineand the second metal line, and an upper surface of the other one of thefirst contact plug and the second contact plug may be disposed on asecond level, lower than the first level, and connected to the other oneof the first metal line and the second metal line by a metal via.

According to an example embodiment of the present disclosure, a methodof manufacturing a semiconductor device may include: preparing asubstrate having a gate structure and a source/drain region formed at aside of the gate structure; forming a first interlayer insulating layerover the gate structure and the source/drain region on the substrate;forming a first contact plug connected to the source/drain regionthrough the first interlayer insulating layer; forming a secondinterlayer insulating layer on the first interlayer insulating layer andthe first contact plug; forming a second contact plug connected to thegate structure through the first interlayer insulating layer and thesecond interlayer insulating layer; and forming a first metal lineconnected to the first contact plug through a metal via formed in thesecond interlayer insulating layer, and a second metal line connected tothe second contact plug on the second interlayer insulating layer.

According to an example embodiment of the present disclosure, asemiconductor device may include: a substrate; a gate structure and asource/drain region disposed on the substrate; a first interlayerinsulating layer disposed over the gate structure and the source/drainregion; a first contact plug disposed in the first interlayer insulatinglayer to connect the source/drain region, with a top surface of thefirst contact plug and a top surface of the first interlayer insulatinglayer being at a first level; a second interlayer insulating layerdisposed on the first interlayer insulating layer; a second contact plugdisposed in the first and second interlayer insulating layers to connectthe gate structure, with a top surface of the second contact plug and atop surface of the second interlayer insulating layer being at a secondlevel, higher than the first level; a first metal line disposed on thesecond interlayer insulating layer, the first metal line including ametal via disposed in the second interlayer insulating layer to connectthe first contact plug, with a top surface of the metal via being at thesecond level; and a second metal line disposed on the second interlayerinsulating layer to directly connect the second contact plug at thesecond level.

BRIEF DESCRIPTION OF THE DRAWINGS

The above, and other features of the present disclosure will be moreclearly understood from the following detailed description taken inconjunction with the accompanying drawings, in which:

FIG. 1 is a layout of a semiconductor device according to an exampleembodiment of the present disclosure;

FIGS. 2A and 2B are cross-sectional views taken along lines I1-I1′ andI2-I2′ of FIG. 1, respectively;

FIG. 2C is a cross-sectional view taken along line II-II′ of FIG. 1;

FIGS. 3, 4, 5, 6, 7, 8, 9, 10A, 11A, 12A, 13A, 14A, and 15A areperspective views illustrating a method of manufacturing a semiconductordevice according to an example embodiment of the present disclosure;

FIGS. 10B, 10C, 11B, 11C, 12B, 13B, 14B, and 15B are cross-sectionalviews illustrating a method of manufacturing a semiconductor deviceaccording to an example embodiment of the present disclosure;

FIG. 16 is a cross-sectional view of a semiconductor device according toan example embodiment of the present disclosure;

FIG. 17 is a layout of a semiconductor device according to an exampleembodiment of the present disclosure;

FIG. 18 is a cross-sectional view of a semiconductor device according toan example embodiment of the present disclosure;

FIG. 19 is a circuit diagram of a static random access memory (SRAM)cell including a semiconductor device according to an example embodimentof the present disclosure; and

FIG. 20 is a block diagram of a storage device including a semiconductordevice according to an exemplary embodiment of the present disclosure.

Since the drawings in FIGS. 1-20 are intended for illustrative purposes,the elements in the drawings are not necessarily drawn to scale. Forexample, some of the elements may be enlarged or exaggerated for claritypurpose.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 is a layout of a semiconductor device according to an exampleembodiment of the present disclosure. FIGS. 2A and 2B arecross-sectional views taken along lines I1-I1′ and I2-I2′ of FIG. 1,respectively. FIG. 2C is a cross-sectional view taken along line II-II′of FIG. 1.

Referring to FIGS. 1 and 2C, a semiconductor device 100 may include asubstrate 101 having three fin-type active regions FAs. The threefin-type active regions FAs may extend in a first direction, forexample, an X direction, and may be arranged and spaced apart in asecond direction, for example, a Y direction.

The substrate 101 may have an upper surface extending in the X and Ydirections. The substrate 101 may include a semiconductor such as, forexample, silicon (Si) or germanium (Ge), or a compound semiconductorsuch as, for example, silicon germanium (SiGe), silicon carbide (SiC),gallium arsenide (GaAs), indium arsenide (InAs), aluminum galliumarsenide (AlGaAs), indium gallium arsenide (InGaAs) or indium phosphide(InP). In an example embodiment of the present disclosure, the substrate101 may have a silicon on insulator (SOI) structure. The substrate 101may include a conductive region, for example, a well doped with animpurity or a substrate doped with an impurity.

Side walls of a lower portion of the three fin-type active regions FAsdisposed on the substrate 101 may be covered by a device separator 107,and the three fin-type active regions FAs may protrude upwardly throughthe device separator 107 in a direction, for example, in a Z direction,perpendicular to the upper surface (which is on an X-Y plane) of thesubstrate 101. A bottom level of each of the three fin-type activeregions FAs may be indicated by dotted lines BL in FIGS. 2A and 2B. Thedevice separator 107 may be formed to limit and/or define an activeregion, for example, the fin-type active region FA, of the substrate101.

As illustrated in FIGS. 2A and 2B, source/drain regions 110 may have araised source/drain (RSD) structure having an upper surface disposed ona level higher than that of an upper surface of the fin-type activeregion FA. RSD structure may reduce resistance caused by thin fins. Thesource/drain regions 110 may include a semiconductor layer epitaxiallygrown from the fin-type active region FA. In an example embodiment ofthe present disclosure, the source/drain regions 110 may have anembedded SiGe structure including a plurality of selectively epitaxiallygrown SiGe layers. The plurality of SiGe layers may have differentcontents of Ge. The source/drain regions 110 may have a structure inwhich the three fin-type active regions FAs may be merged with oneanother in a growth process. That is, one source/drain region grown fromone fin-type active region may be merged with one or more source/drainregions grown from adjacent fin-type active regions.

As illustrated in FIG. 2C, the source/drain regions 110 may have apentagonal shape, but the present disclosure is not limited thereto, andthe source/drain regions 110 may have various shapes. For example, thesource/drain regions 110 may have one of polygonal, circular, andrectangular shapes.

As illustrated in FIG. 1, three gate structures 140 may extend in the Ydirection over the upper surfaces of the three fin-type active regionsFAs, and may be arranged and spaced apart in the X direction. Asillustrated in FIGS. 2A and 2B, each of the three gate structures 140may have a gate insulating layer 142 and a gate electrode 145. The gateinsulating layer 142 and the gate electrode 145 may extend in the Ydirection and may intersect the fin-type active region FA extending inthe X direction, while covering the upper surface and both side walls ofthe fin-type active region FA and an upper surface of the deviceseparator 107. A plurality of metal-oxide semiconductor (MOS)transistors may be formed in regions in which the fin-type active regionFA and a plurality of gate structures 140 intersect. Each of the MOStransistors may have a three-dimensional structure in which channels areformed in portions of the fin-type active region at locations where thegate structures cover the upper surface and both side walls of thefin-type active region FA.

Both side walls of the gate structure 140 may be covered by insulatingspacers 150. The insulating spacers 150 may include, for example, asilicon nitride, a silicon oxynitride, or a combination thereof.

The gate insulating layer 142 may include, for example, a silicon oxidelayer, a high-k dielectric layer, or a combination thereof. The high-kdielectric layer may include a material having a dielectric constantgreater than that of a silicon oxide layer, for example, having adielectric constant of about 10 to about 25. For example, the high-kdielectric layer may include at least one of a hafnium oxide, a hafniumoxynitride, a hafnium silicon oxide, a lanthanum oxide, a lanthanumaluminum oxide, a zirconium oxide, a zirconium silicon oxide, a tantalumoxide, a titanium oxide, a barium strontium titanium oxide, a bariumtitanium oxide, a strontium titanium oxide, an yttrium oxide, analuminum oxide, a lead scandium tantalum oxide, a lead zinc niobate, andcombinations thereof, but the present disclosure is not limited thereto.The gate insulating layer 142 may be formed by, for example, an atomiclayer deposition (ALD) process, a chemical vapor deposition (CVD)process, or a physical vapor deposition (PVD).

The gate electrode 145 may include a first gate electrode 145 a and asecond gate electrode 145 b. The first gate electrode 145 a may adjust awork function. The second gate electrode 145 b may fill a space formedon the first gate electrode 145 a. The first gate electrode 145 a mayserve as an antidiffusion layer for the second gate electrode 145 b, butthe present disclosure is not limited thereto.

The first and second gate electrodes 145 a and 145 b may includedifferent materials. The first gate electrode 145 a may include, forexample, a metal nitride such as a titanium nitride (TiN), a tantalumnitride (TaN), or a tungsten nitride (WN). The second gate electrode 145b may include, for example, a metal material such as aluminum (Al),tungsten (W), or molybdenum (Mo), or a semiconductor material such asdoped polycrystalline silicon.

An inter-gate insulating layer 162 may be formed between the gatestructures 140. The inter-gate insulating layer 162 may cover thesource/drain regions 110 among the three gate structures 140. Theinter-gate insulating layer 162 may include, for example, a siliconoxide layer or a silicon nitride layer, but the present disclosure isnot limited thereto.

A first interlayer insulating layer 164 and a second interlayerinsulating layer 166 may be formed on the inter-gate insulating layer162 and the gate structure 140. The first and second interlayerinsulating layers 164 and 166 may include, for example, a tetra ethylortho silicate (TEOS) layer, an undoped silicate glass (USG) layer, aphosphosilicate glass (PSG) layer, a borosilicate glass (BSG) layer, aborophosphosilicate glass (BPSG) layer, a fluoride silicate glass (FSG)layer, a spin on glass (SOG) layer, a tonen silazene (TOSZ) layer, orany combination thereof. The first and second interlayer insulatinglayers 164 and 166 may be formed by, for example, a CVD process, a spincoating process, or the like. In an example embodiment of the presentdisclosure, the first interlayer insulating layer 164 may be a TOSZlayer, and the second interlayer insulating layer 166 may be a TEOSlayer.

In an example embodiment of the present disclosure, the inter-gateinsulating layer 162 and the first interlayer insulating layer 164 mayhave a blocking insulating layer formed therebetween. The blockinginsulating layer may prevent a foreign substance such as oxygen frominfiltrating into the gate electrode 145. In an example embodiment ofthe present disclosure, the inter-gate insulating layer 162 and thefirst interlayer insulating layer 164 may be implemented as a singleinterlayer insulating layer covering the source/drain region 110 and thegate structure 140.

As illustrated in FIGS. 2A and 2B, the source/drain regions 110 may bedisposed within the fin-type active region FA at both sides of the gatestructure 140. First contact plugs 180A may be connected to thesource/drain regions 110, and may extend in a third direction, forexample, in the Z direction, perpendicular to the upper surface of thesubstrate 101. That is, the first contact plugs 180A may extend in asubstantially vertical direction from an upper surface of the substrate101. A second contact plug 180B may be connected to the gate electrode145 of the gate structure 140, and may extend in the Z direction. Thesecond contact plug 180B may also extend in a substantially verticaldirection from an upper surface of the substrate 101. The first andsecond contact plugs 180A and 180B, employed in this example embodiment,may have different heights. For example, upper surfaces of the firstcontact plugs 180A and an upper surface of the second contact plug 180Bmay be disposed on different levels L1 and L2, respectively. The levelL1 is lower than the level L2. In an example embodiment of the presentdisclosure, the upper surfaces of the first contact plugs 180A and theupper surface of the second contact plug 180B may be disposed on thelevels L2 and L1, respectively.

Referring to FIGS. 2A and 2B, the first contact plugs 180A may beconnected to the source/drain regions 110 through the inter-gateinsulating layer 162 and the first interlayer insulating layer 164. Thefirst contact plugs 180A may be surrounded by the first interlayerinsulating layer 164 to be insulated from other conductive elements. Thefirst contact plugs 180A may have spacers 172 formed along side wallsthereof. The spacers 172 may include, for example, a silicon nitride ora silicon oxide.

The source/drain regions 110 may have upper surfaces in which recesses110R may be formed. The recesses 110R may have a sufficient depth D sothat portions of the first contact plugs 180A may be disposed therein.As illustrated in FIG. 2C, the recesses 110R may have a relatively flatlower surface, but the present disclosure is not limited thereto. Forexample, the recesses 110R may be bent in the Y direction. The firstcontact plugs 180A may include conductive materials 186, extending fromthe insides of the recesses 110R in the third direction, for example, inthe Z direction, perpendicular to the upper surface (which is on the X-Yplane) of the substrate 101. The conductive materials 186 may include,for example, tungsten (W), cobalt (Co), an alloy thereof, or acombination thereof.

The first contact plugs 180A may include metal silicide layers 182 toreduce contact resistance with the source/drain regions 110 which arethe doping regions. For example, the metal silicide layers 182 may reactwith a semiconductor material, such as silicon (Si), SiGe, or germanium(Ge), of the source/drain regions 110 to be formed on the upper surfacesof the source/drain regions 110. In an example embodiment of the presentdisclosure, the metal silicide layers 182 may have a compositionrepresented by MSi_(x)D_(y). Here, M is a metal, D is an element havinga component different from M and silicon (Si), x is greater than 0 andequal to or less than 3, and y is equal to or greater than 0 and equalto or less than 1. M may include, for example, titanium (Ti), cobalt(Co), nickel (Ni), tantalum (Ta), platinum (Pt), or a combinationthereof, and D may include, for example, germanium (Ge), carbon (C),argon (Ar), krypton (Kr), xenon (Xe), or a combination thereof.

The first contact plugs 180A may include conductive barrier layers 184disposed on lateral surfaces and lower surfaces thereof. The conductivebarrier layers 184 may include a conductive metal nitride layer. Forexample, the conductive barrier layers 184 may include at least one ofTiN, TaN, AlN, WN, and combinations thereof.

Based on an X-Y plane, cross sections of the first contact plugs 180Aemployed in this example embodiment may have a bar shape extending inthe Y direction, as illustrated in FIGS. 1 and 2C. However, the shape ofthe cross sections of the first contact plugs 180A is not limitedthereto, and the cross sections of the first contact plugs 180A mayhave, for example, a circular, oval, or polygonal shape.

Referring to FIG. 2A, the second contact plug 180B may be connected tothe gate electrode 145 through the first and second interlayerinsulating layers 164 and 166. Similar to the first contact plugs 180A,the second contact plug 180B may also have a spacer 172 formed alongside walls thereof. The second contact plug 180B may include aconductive material 186 extending in the Z direction, and a conductivebarrier layer 184 disposed on lateral surfaces and a lower surface ofthe conductive material 186. As illustrated in FIGS. 1 and 2C, based onthe X-Y plane, a cross section of the second contact plug 180B employedin this example embodiment may have a hole shape. However, the shape ofthe cross section of the second contact plug 180B is not limitedthereto, and the cross section of the second contact plug 180B may have,for example, a circular, oval, or polygonal shape.

As illustrated in FIG. 2A, the upper surfaces of the first contact plugs180A may be disposed on the level L1 which is lower than the level L2 ofan upper surface of the second contact plug 180B. The first and secondcontact plugs 180A and 180B may be formed through creating contact holesor trenches from planes at different levels, and thus in this exampleembodiment, a distance d between the first and second contact plugs 180Aand 180B may be narrower than that between two contact holes to which aphotolithography process is applied on the same plane at the same level.For example, the distance d between the first and second contact plugs180A and 180B may be about 20 nm or less, and further about 10 nm orless. The distance d is the shortest distance between the first andsecond contact plugs 180A and 180B, for example, in X direction as shownin FIG. 2A.

The second interlayer insulating layer 166 may have first metal lines190A and a second metal line 190B disposed thereon. The first metallines 190A may have metal vias V disposed within the second interlayerinsulating layer 166, and may be connected to the first contact plugs180A through the metal vias V. Conversely, the second metal line 190Bmay be directly connected to the second contact plug 180B without ametal via. In detail, the upper surface of the second contact plug 180Bmay be exposed together with an upper surface of the second interlayerinsulating layer 166, and thus the second metal line 190B may bedirectly connected to the second contact plug 180B on the secondinterlayer insulating layer 166.

As described above, the second contact plug 180B may be disposed up tothe same level L2 as that of the second metal line 190B is disposed on,unlike the case of the first contact plugs 180A, which is disposed up tothe level L1, and may thus be directly connected to the second metalline 190B without a via structure. Thus, the present disclosure mayreduce the number of metal vias while maintaining a layout design ofrelated art. As a result, the likelihood of contact defects due to ametal via may be reduced. An example of contact defects caused by themetal via is via open.

In the related art, the upper surfaces of the first contact plugs may becoplanar with the upper surface of the second contact plug. Both thefirst metal lines and the second metal line may be connected to thefirst contact plugs and the second contact plug, respectively, throughmetal vias. As a result, in the related art, larger spacing is requiredbetween the first contact plugs and the second contact plug. Inaddition, in the related art, the first contact plugs and the secondcontact plug may not have different heights, because it may lead todifferent heights in metal vias connected to the first contact plugs andthe second contact plug, and a structure with different heights in metalvias is difficult for back end of line (BEOL) integration. On the otherhand, no change to the metal level process, for example, the first metallevel (Ml) process is needed for fabricating the semiconductor devicedescribed in this example embodiment of the present disclosure.

The first and second metal lines 190A and 190B employed in this exampleembodiment may be formed by a damascene process. The second interlayerinsulating layer 166 may include a low-k dielectric layer 168 formedaround the first and second metal lines 190A and 190B and used in thedamascene process. The low-k dielectric layer 168 may include, forexample, a silicon oxide layer, a silicon oxynitride layer, a siliconoxycarbide (SiOC) layer, a hydrogenated silicon oxycarbide (SiCOH)layer, or a combination thereof.

The first and second metal lines 190A and 190B may include, for example,copper (Cu) ora copper-containing alloy. The metal vias V may beintegrated with the first metal lines 190A to become part of the firstmetal lines 190A, and may be formed of the same metal or alloy as thefirst metal line 190A.

In this example embodiment, the semiconductor device 100 may furtherinclude an etch stop layer 174 disposed between the first and secondinterlayer insulating layers 164 and 166. The etch stop layer 174 mayfunction to retard etching of a hole for the metal via V when the holefor the metal via V is being formed, while preventing a metal, forexample, copper (Cu), which forms the first and second metal lines 190Aand 190B and the metal via V, from diffusing into a lower region of thefirst and second metal lines 190A and 190B and the metal via V. However,the function of the etch stop layer 174 is not limited thereto, and theetch stop layer 174 may include an aluminum nitride (AlN).

FIGS. 3, 4, 5, 6, 7, 8, 9, 10A, 11A, 12A, 13A, 14A, and 15A areperspective views illustrating a method of manufacturing a semiconductordevice according to an example embodiment of the present disclosure.FIGS. 10B, 10C, 11B, 11C, 12B, 13B, 14B, and 15B are cross-sectionalviews illustrating a method of manufacturing a semiconductor deviceaccording to an example embodiment of the present disclosure. Thisprocess of manufacturing a semiconductor device may be understood asbeing performed for a portion of the semiconductor device correspondingto “SU” in the layout illustrated in FIG. 1.

Referring to FIG. 3, trenches TI, defining active fins 105, may beformed by patterning a substrate 101.

A pad oxide pattern 122 and a mask pattern 124 may be formed on thesubstrate 101 first. The pad oxide pattern 122 may be a layer to protectupper surfaces of the active fins 105 (also referred to as a “fin-typeactive region FA” in this specification). In an example embodiment ofthe present disclosure, the pad oxide pattern 122 may be removed. Themask pattern 124 may be a mask layer for patterning the substrate 101,and may include, for example, a silicon nitride, a carbon-containingmaterial, or the like. The mask pattern 124 may have a multilayerstructure.

The trenches TI may be formed by anisotropically etching the substrate101, using the pad oxide pattern 122 and the mask pattern 124 as anetching mask. The trenches TI may have a high aspect ratio, and thus thewidth thereof may be narrower downwardly. Accordingly, the width of theactive fins 105 may be narrower upwardly.

In an example embodiment of the present disclosure, the substrate 101may have a P-channel metal-oxide-semiconductor field-effect transistor(P-MOSFET) region or an N-channel metal-oxide-semiconductor field-effecttransistor (N-MOSFET) region, and the active fins 105 may include P-typeor N-type impurity diffusion regions according to a desired channel typeof a metal-oxide-semiconductor field-effect transistor (MOSFET).

Referring to FIG. 4, a device separator 107 filling the trenches TI maybe formed.

First, a process of filling the trenches TI with an insulating materialand then planarizing the filled trenches TI may be performed. During theprocess, at least portions of the pad oxide pattern 122 and the maskpattern 124 may be removed. In an example embodiment of the presentdisclosure, a liner layer having a relatively reduced thickness may beformed within the trenches TI, and then the trenches TI may be filledwith the insulating material.

Subsequently, a process of allowing the active fins 105 to protrude fromthe substrate 101 by etching back the insulating material filling thetrenches TI may be performed. This process may be performed with, forexample, a wet etching process using at least a portion of the pad oxidepattern 122 as an etching mask. Accordingly, the active fins 105 mayprotrude upwardly by a predetermined height, and the predeterminedheight may vary. During the wet etching process, the pad oxide pattern122 may also be removed. The device separator 107 may include, forexample, a silicon oxide layer, a silicon nitride layer, a siliconoxynitride layer, or a combination thereof.

Referring to FIG. 5, a dummy gate insulating layer 132, a dummy gateelectrode 135, and an insulating spacer 150 may be formed to extend inthe Y direction while intersecting the active fins 105 which extend inthe X direction.

The dummy gate insulating layer 132 and the dummy gate electrode 135 mayform a desired dummy gate (DG) structure by performing an etchingprocess using a mask pattern layer 136 as an etching mask. The dummygate insulating layer 132 and the dummy gate electrode 135 may be formedin regions in which the gate insulating layer 142 and the first andsecond gate electrodes 145 a and 145 b (refer to FIG. 2A) are to beformed, and may be removed during a subsequent process. The dummy gateinsulating layer 132 may include, for example, a silicon oxide, and thedummy gate electrode 135 may include, for example, polycrystallinesilicon.

The insulating spacer 150 may be formed by forming a conformal layerhaving a uniform thickness on portions of the dummy gate insulatinglayer 132, the dummy gate electrode 135, and the mask pattern layer 136,and then anisotropically etching the formed layer. The insulating spacer150 may also have a structure in which a plurality of layers arestacked.

Referring to FIG. 6, source/drain regions 110, including crystallinesemiconductor regions 110A, may be formed on portions of the active fins105 exposed at both sides of the dummy gate (DG) structure.

The crystalline semiconductor regions 110A may be formed by a selectiveepitaxial growth (SEG) process. The crystalline semiconductor regions110A formed on the active fins 105 may be connected to each other in theSEG process to form connecting portions ME. The crystallinesemiconductor regions 110A grown on the respective portions of theactive fins 105 may include germanium (Ge) having the same or differentconcentrations. The crystalline semiconductor regions 110A may be grownalong a crystallographically stable surface in the SEG process to have apentagonal or hexagonal shape, as illustrated in FIG. 6. The shape ofcross sections of the source/drain regions 110 cut along a Y-Z planethereof is not limited thereto, and may have, for example, a polygonalshape such as a quadrangular shape, a circular shape, or an oval shape.

The source/drain regions 110 may have upper surfaces disposed on a levelhigher than that of upper surfaces of the active fins 105 to form araised source/drain (RSD) structure. The source/drain regions 110 mayinclude a semiconductor layer doped with an impurity. In an exampleembodiment of the present disclosure, the source/drain regions 110 mayinclude, for example, silicon (Si), SiGe, or SiC doped with an impurity.

Referring to FIG. 7, an inter-gate insulating layer 162 may be formed onthe source/drain regions 110.

In an example embodiment of the present disclosure, in the process offorming the inter-gate insulating layer 162, an insulating layer may beformed to have a sufficient thickness to cover the source/drain regions110, the dummy gate (DG) structure, and the insulating spacer 150.Thereafter, a product in which the insulating layer is formed may beplanarized to allow the dummy gate (DG) structure to be exposed. In thisplanarizing process, the mask pattern layer 136 may be removed, and anupper surface of the dummy gate electrode 135 may be exposed. Theinter-gate insulating layer 162 may include, for example, at least oneof an oxide, a nitride, and an oxynitride.

Referring to FIG. 8, a gate structure formation region E (also referredto as an “opening portion E”) may be provided by removing the dummy gateinsulating layer 132 and the dummy gate electrode 135.

The dummy gate insulating layer 132 and the dummy gate electrode 135 maybe selectively removed from the device separator 107 and the active fins105 disposed therebelow, and thus the opening portion E, exposingportions of the device separator 107 and the active fins 105, may beformed. A process of removing the dummy gate insulating layer 132 andthe dummy gate electrode 135 may be performed using at least one of adry etching process and a wet etching process.

Referring to FIG. 9, a gate structure 140 may be formed by forming agate insulating layer 142 and first and second gate electrodes 145 a and145 b within the opening portion E.

The gate insulating layer 142 may be substantially conformally formedalong side walls and a lower surface of the opening portion E. The gateinsulating layer 142 may include, for example, an oxide, a nitride, orthe above-mentioned high-k dielectric layer. The first and second gateelectrodes 145 a and 145 b may include the above-mentioned metal orsemiconductor material.

FIGS. 10A through 10C illustrate a subsequent process. FIGS. 10B and 10Cillustrate cross sections taken along lines A-A′ and B-B′ of FIG. 10A,respectively. In this process, a first interlayer insulating layer 164may be formed first, and then first contact holes H1 may be formed toconnect the source/drain regions 110.

Each of the first contact holes H1 may define a region in which thefirst contact plug 180A (refer to FIG. 2A) is to be formed, and may beformed by removing portions of the inter-gate insulating layer 162 andthe first interlayer insulating layer 164, using a separate etching masklayer such as a photoresist pattern during the etching process. In sucha process of forming the first contact holes H1, portions of upperportions of the source/drain regions 110 may be removed along with theinter-gate insulating layer 162 and the first interlayer insulatinglayer 164 to form recesses 110R having a predetermined depth D (refer toFIGS. 10B and 10C). In this example embodiment, as illustrated in FIG.10C, lower surfaces of the recesses 110R are illustrated as beingsubstantially flat, but may be bent similarly to the upper surfaces ofthe source/drain regions 110. Such a bent profile may be obtained bysetting different concentrations (a difference between etching rates) ofat least one element, for example, germanium (Ge), included in thesource/drain regions 110, to different regions.

A subsequent process is illustrated in FIGS. 11A through 11C in a mannersimilar to those of FIGS. 10A through 10C. FIGS. 11B and 11C illustratecross sections taken along lines A-A′ and B-B′ of FIG. 11A,respectively.

Referring to FIGS. 11A through 11C, first contact plugs 180A may beformed by filling the first contact holes H1 with a conductive material186.

Prior to filling the conductive material 186, a process of forming metalsilicide layers 182 and conductive barrier layers 184 may be performed.After metal layers are deposited on surfaces of the source/drain regions110, the metal silicide layers 182 may be formed by allowing the metallayers to react with materials of the source/drain regions 110 in thisprocess or a process subsequent thereto. The conductive barrier layers184 may be deposited on upper surfaces of the metal silicide layers 182and internal side walls of the first contact holes H1 prior to fillingthe conductive material 186. In this example embodiment, prior toforming the first contact plugs 180A, spacers 172 may be formed on theinternal side walls of the first contact holes H1, using an insulatingmaterial such as, for example, a silicon oxide or a silicon nitride.

FIGS. 12A, 13A, 14A, and 15A are perspective views illustratingsubsequent processes, and FIGS. 12B, 13B, 14B, and 15B arecross-sectional views taken along lines A-A′ of FIGS. 12A, 13A, 14A, and15A.

Referring to FIGS. 12A and 12B, a second interlayer insulating layer 166may be formed on the first interlayer insulating layer 164, in which thefirst contact plugs 180A are formed, and a second contact hole H2connected to the gate electrode 145 may be formed in the first andsecond interlayer insulating layers 164 and 166.

The second interlayer insulating layer 166 may include an insulatingmaterial, and may include, for example, at least one of an oxide layer,a nitride layer, and an oxynitride layer. Prior to forming the secondinterlayer insulating layer 166, an etch stop layer 174 may be formed onthe first interlayer insulating layer 164. The etch stop layer 174 mayfunction to prevent a metal, such as copper (Cu), from forming a metalline or the like by its diffusion to a lower portion of the etch stoplayer 174 in which the fin-type active region FA is disposed. However,the function of the etch stop layer 174 is not limited thereto, and theetch stop layer 174 may include an aluminum nitride (AlN).

The second contact hole H2 formed in this process may define a region inwhich the second contact plug 180B (refer to FIG. 2A) is to be formed,and similar to the first contact holes H1, the second contact hole H2may be formed by removing portions of the first and second interlayerinsulating layers 164 and 166, using a separate etching mask layer suchas a photoresist pattern during the etching process. As described above,the second contact hole H2 may be formed with the upper surface in aplane at a level L2 which is different from a level L1 of the uppersurfaces of the first contact holes H1, and thus a distance between thefirst contact holes H1 and the second contact hole H2 may be less thanthat between the first contact holes H1 and the second contact hole H2formed with their upper surfaces in the same plane at the same level.

In this example embodiment, the first contact holes H1 for the firstcontact plugs 180A may have a bar shape extending in the Y direction,while the second contact hole H2 for a second contact plug 180B (referto FIG. 13A) may have a simple hole shape. Such a design may beassociated with the layout illustrated in FIG. 1. In an exampleembodiment of the present disclosure, the shapes of the first contactplugs 180A and the second contact plug 180B may be modified to haveother shapes than those described above. In this process, spacers 172may be formed of an insulating material such as, for example, a siliconoxide or a silicon nitride, on internal side walls of the second contacthole H2.

Referring to FIGS. 13A and 13B, the second contact plug 180B may beformed by filling the second contact hole H2 with a conductive material186.

Similar to the process of forming the first contact plugs 180A, prior tofilling the conductive material 186, a process of forming a conductivebarrier layer 184 may be performed. The second contact plug 180B may bein direct contact with the gate electrode 145, which is an electrodebody, and thus, as illustrated in this example embodiment, a metalsilicide layer for reducing contact resistance may not be required.

Subsequently, first metal lines 190A and a second metal line 190B,connected to the first contact plugs 180A and the second contact plug180B, respectively, may be formed on the second interlayer insulatinglayer 166. This process of forming the first metal lines 190A and thesecond metal line 190B may be performed using a damascene process.

First, as illustrated in FIGS. 14A and 14B, a low-k dielectric layer168, having first regions O1 and a second region O2 open, may be formedon the second interlayer insulating layer 166. The first and secondregions O1 and O2 may define regions for the first and second metallines 190A and 190B, respectively. In this example embodiment, the low-kdielectric layer 168 may be illustrated as being implemented as a linearshape, but if necessary, the shape of the first and second regions O1and O2 may vary. The low-k dielectric layer 168 may include, forexample, a silicon oxide layer, a silicon oxynitride layer, a siliconoxycarbide (SiOC) layer, a hydrogenated silicon oxycarbide (SiCOH)layer, or a combination thereof.

Holes HA, connected to the first contact plugs 180A, may be formed inportions of the second interlayer insulating layer 166 exposed by thefirst regions O1. Upper surface regions of the first interlayerinsulating layer 164 may be exposed by the holes HA, and the uppersurfaces of the first contact plugs 180A may be exposed with the exposedupper surface regions of the first interlayer insulating layer 164. Thesecond contact plug 180B may be disposed up to the upper surface of thesecond interlayer insulating layer 166, differently from the firstcontact plugs 180A being disposed, and thus the upper surface of thesecond contact plug 180B may be exposed together with a portion of thesecond interlayer insulating layer 166 by the second region O2.

Subsequently, as illustrated in FIGS. 15A and 15B, the first and secondmetal lines 190A and 190B may be formed and connected to the first andsecond contact plugs 180A and 180B, respectively.

This process of forming the first and second metal lines 190A and 190Bmay be performed by forming metal layers to fill the holes HA and thefirst and second regions O1 and O2, and then planarizing the metallayers so as to expose an upper surface of the low-k dielectric layer168. Such metal layers may include, for example, copper (Cu) or acopper-containing alloy.

The first and second metal lines 190A and 190B may be formed on thesecond interlayer insulating layer 166. The first metal lines 190A maybe connected to the first contact plugs 180A by metal vias V, while thesecond metal line 190B may be directly connected to the second contactplug 180B. As described above, the second contact plug 180B may bedisposed up to the same level L2 as that of the second metal line 190Bis disposed on and from, and may thus be directly connected to thesecond metal line 190B without a via structure. The metal vias V may beintegrated with the first metal lines 190A to become part of the firstmetal lines 190A, and may be formed of the same metal or alloy as thatof the first metal lines 190A.

FIG. 16 is a cross-sectional view of a semiconductor device according toan example embodiment of the present disclosure.

Referring to FIG. 16, a semiconductor device 100′ according to anexample embodiment of the present disclosure may include first contactplugs 180A′, and a second contact plug 180B′ disposed up to levelsopposite the levels L1 and L2 of the first contact plugs 180A and thesecond contact plug 180B illustrated in the above example embodiment.That is, the upper surfaces of the first contact plugs 180A′ are at thelevel L2, and the upper surface of the second contact plug 180B′ is atthe level L1.

In the semiconductor device 100′ described above, the first contactplugs 180A′ may be formed through an inter-gate insulating layer 162, afirst interlayer insulating layer 164, and a second interlayerinsulating layer 166, and the second contact plug 180B′ may be formedthrough the first interlayer insulating layer 164. Thus, upper surfacesof the first contact plugs 180A′ may be disposed on a level L2 higherthan a level L1 of an upper surface of the second contact plug 180B′.

In this example embodiment, the first and second metal lines 190A′ and190B′ may be formed on the second interlayer insulating layer 166. Thefirst metal lines 190A′ may be directly connected to the first contactplugs 180A′, while the second metal line 190B′ may be connected to thesecond contact plug 180B′ by a metal via V. The metal via V may beintegrated with the second metal line 190B′, and may be part of thesecond metal line 190B′. In this example embodiment, the first contactplugs 180A′ and the first metal lines 190A′ may be directly connected toeach other without having metal vias V disposed therebetween, therebyreducing the likelihood of contact defects caused by metal vias. Viaopen is one of the contact defects caused by metal vias.

FIG. 17 is a layout of a semiconductor device according to an exampleembodiment of the present disclosure. FIG. 18 is a cross-sectional viewtaken along lines X-X′ and Y-Y′ of FIG. 17.

Referring to FIGS. 18 and 19, a semiconductor device 200 according to anexample embodiment of the present disclosure may include a semiconductorsubstrate 201 having a gate structure 240 in an active region ACT. In anexample embodiment of the present disclosure, the active region ACT mayinclude a fin-type active region FA.

The semiconductor substrate 201 employed in this example embodiment maybe a monocrystalline silicon substrate. For example, the semiconductorsubstrate 201 may be a silicon substrate having (100) plane. In anexample embodiment of the present disclosure, the semiconductorsubstrate 201 may be, for example, an SOI substrate, a Ge substrate, ora SiGe substrate.

The active region ACT may include, for example, silicon (Si) or SiGe.The active region ACT may be defined by a device separator 205. Thesemiconductor substrate 201 may include a well region doped with animpurity to form metal oxide semiconductor (MOS) transistors. In anexample embodiment of the present disclosure, the semiconductorsubstrate 201 may include an n-type well for forming p-channel metaloxide semiconductor (PMOS) transistors.

The gate structure 240 may include a gate insulating layer 242 and agate electrode 245 sequentially disposed in the active region ACT. Thegate insulating layer 242 may include at least one of a silicon oxidelayer, a silicon nitride layer, a silicon oxynitride layer, and a high-kdielectric layer. The high-k dielectric layer may include theabove-mentioned insulating material having a dielectric constant greaterthan that of a silicon oxide layer.

The gate electrode 245 may be disposed on the gate insulating layer 242and may traverse the active region ACT. The gate electrode 245 may beformed of, for example, a polycrystalline silicon layer doped with animpurity. In an example embodiment of the present disclosure, the gateelectrode 245 may include a conductive material having relatively lowresistivity and a high work function. For example, the gate electrode245 may include at least one of metals, such as tungsten (W) andmolybdenum (Mo), and conductive metal compounds, such as titaniumnitride, tantalum nitride, tungsten nitride, and titanium aluminumnitride.

Spacers 250 may be disposed on both side walls of the gate structure240. The spacers 250 may be, for example, a silicon oxide layer or asilicon nitride layer. Impurity regions 243 may be formed on portions ofthe active region ACT disposed at both sides of the gate structure 240.As illustrated in this example embodiment, in the case of a PMOStransistor, the impurity regions 243 may be doped with a p-type impuritysuch as boron (B).

Source/drain regions 210 may be obtained by forming recesses throughselective etching of portions of the active region ACT disposed at bothsides of the gate structure 240, and then forming SiGe epitaxial layerswithin the recesses using an SEG process. As illustrated in this exampleembodiment, in the case of a PMOS transistor, to apply compressionstress to channel regions, SiGe epitaxial layers having a latticeconstant greater than that of silicon included in the semiconductorsubstrate 201 may be formed.

The source/drain regions 210 may be formed of, for example, silicongermanium (Si_(1-x)Ge^(x), 0<x<1). A lattice constant of Ge crystals maybe greater than that of Si crystals, and thus as Si atoms are replacedby Ge atoms within a silicon crystalline lattice, a lattice constant ofSi_(1-x)Ge_(x) (0<x<1) may be greater than that of the si crystals. Whenthe SiGe epitaxial layers are grown in the recesses, compression stressmay be generated in the channel regions of the PMOS transistor. As theconcentration of Ge increases, the lattice of the SiGe epitaxial layersmay become greater, and thus compression stress applied to the channelregions may increase.

Metal silicide layers 282 may be disposed on the source/drain regions210. Process of forming the metal silicide layers 282 may includedepositing metal layers on surfaces of the source/drain regions 210first, then the metal layers may react with the SiGe epitaxial layers toform metal silicide layers containing germanium (Ge).

A first interlayer insulating layer 264 and a second interlayerinsulating layer 266 may be sequentially disposed on the semiconductorsubstrate 201. The first and second interlayer insulating layers 264 and266 may be formed of the above-described material, and by a CVD process,a spin coating process, or the like. If necessary, the first interlayerinsulating layer 264 may be formed, and then a process of planarizingthe first interlayer insulating layer 264 may be performed. Asillustrated in this example embodiment, prior to forming the firstinterlayer insulating layer 264, a first etch stop layer 273 may beconformally formed along surfaces of the gate structures 240 disposed onthe semiconductor substrate 201, and a second etch stop layer 274 may bedisposed between the first and second interlayer insulating layers 264and 266. The first and second etch stop layers 273 and 274 may include,for example, a silicon nitride, a silicon oxynitride, or an aluminumnitride.

First contact plugs 280A connected to the source/drain regions 210 maybe formed through the first interlayer insulating layer 264 so as toallow the metal silicide layers 282 to be connected to the source/drainregions 210. Each of the first contact plugs 280A may include aconductive material 286, and a conductive barrier layer 284 surroundingthe conductive material 286. A second contact plug 280B may includeelements similar to those of the first contact plugs 280A, and may beconnected to the gate electrode 245 through the first and secondinterlayer insulating layers 264 and 266.

Upper surfaces of the first contact plugs 280A may be disposed on alevel lower than that of an upper surface of the second contact plug280B. The first and second contact plugs 280A and 280B may be formed upto planes having different levels, and thus a distance therebetween maybe reduced. That is, the distance between the first contact plugs 280Aand the second contact plug 280B at the level of the upper surfaces ofthe first contact plugs 280A may be reduced.

The second interlayer insulating layer 266 may have first metal lines290A and a second metal line 290B disposed thereon. The secondinterlayer insulating layer 266 may include a low-k dielectric layer 268formed around the first and second metal lines 290A and 290B and used ina damascene process. The first and second metal lines 290A and 290B mayinclude, for example, copper (Cu) or a copper-containing alloy.

As illustrated in FIG. 18, the first metal lines 290A may have metalvias V disposed within the second interlayer insulating layer 266, andmay be connected to the first contact plugs 280A through the metal viasV. Conversely, the second metal line 290B may be directly connected tothe second contact plug 280B without a metal via. Thus, the presentdisclosure may reduce the number of metal vias while maintaining alayout design of the related art. As a result, the likelihood of contactdefects due to a metal via may be reduced.

FIG. 19 is a circuit diagram of a static random access memory (SRAM)cell including a semiconductor device according to an example embodimentof the present disclosure.

Referring to FIG. 19, the single cell in the SRAM device may include afirst drive transistor TN1, a second drive transistor TN2, a first loadtransistor TP1, a second load transistor TP2, a first access transistorTN3, and a second access transistor TN4. Here, sources of the first andsecond drive transistors TN1 and TN2 may be connected to a ground powersupply voltage VSS line, and sources of the first and second loadtransistors TP1 and TP2 may be connected to a power supply voltage VDDline.

The first drive transistor TN1, formed of an NMOS transistor, and thefirst load transistor TP1, formed of a PMOS transistor, may form a firstinverter, and the second drive transistor TN2, formed of an NMOStransistor, and the second load transistor TP, formed of a PMOS fieldeffect transistor, may form a second inverter. At least one of the firstand second drive transistors TN1 and TN2, the first and second loadtransistors TP1 and TP2, and the first and second access transistors TN3and TN4 may include a semiconductor device according to at least one ofthe example embodiments of the present disclosure described above withreference to FIGS. 1 through 2C and FIGS. 16 through 18.

Output terminals of the first and second inverters may be connected tosources of the first and second access transistors TN3 and TN4,respectively. In addition, input terminals and the output terminals ofthe first and second inverters may intersect each other so as toconfigure a single latch circuit. Drains of the first and second accesstransistors TN3 and TN4 may be connected to first and second bit line BLand/BL, respectively.

FIG. 20 is a block diagram of a storage device including a semiconductordevice according to an example embodiment of the present disclosure.

Referring to FIG. 20, a storage device 1000, according to an exampleembodiment of the present disclosure, may include a controller 1010communicating with a host and memories 1020-1, 1020-2, and 1020-3storing data. The respective memories 1020-1, 1020-2, and 1020-3 mayeach include a semiconductor device according to at least one of theexample embodiments of the present disclosure described above withreference to FIGS. 1 through 2C and FIGS. 16 through 18.

The host communicating with the controller 1010 may be various types ofelectronic devices each of which the storage device 1000 may be embeddedin. The host may be, for example, a smartphone, a digital camera, adesktop PC, a laptop PC, or a media player. The controller 1010 mayreceive a data writing or data reading request transferred by the host,and may generate a command CMD for writing data to the memories 1020-1,1020-2, and 1020-3 or reading data from the memories 1020-1, 1020-2, and1020-3.

As illustrated in FIG. 20, one or more memories 1020-1, 1020-2, and1020-3 may be connected to the controller 1010, in parallel within thestorage device 1000. By connecting the memories 1020-1, 1020-2, and1020-3 to the controller 1010 in parallel, the storage device 1000having a large capacity, such as a solid state drive (SSD), may beimplemented.

As set forth above, according to an example embodiment of the presentdisclosure, upper surfaces of adjacent contact plugs may be disposed ondifferent levels, thereby reducing an interval, such as the distance dshown in FIG. 2A, between the adjacent contact plugs, for example, toabout 10 nm or less. A portion of contact plugs may be directlyconnected to a metal line without using a via structure, thereby abatingcontact defects caused by a via. The interval is the shortest distancebetween the adjacent plugs, and may be located at a level which an uppersurface of one of the adjacent plugs is disposed on.

While exemplary embodiments of the present disclosure have been shownand described above, it will be apparent to those skilled in the artthat modifications and variations could be made without departing fromthe spirit and scope of the present disclosure, as defined by theappended claims.

What is claimed is:
 1. A semiconductor device comprising: a substratehaving an active region; a plurality of active fins protruding from theactive region and extending in a first direction; a gate structuretraversing the plurality of active fins and extending in a seconddirection intersecting the first direction; a source/drain regiondisposed in the plurality of active fins at a side of the gatestructure; an interlayer insulating layer disposed on the gate structureand the source/drain region; a first contact plug extending from thesource/drain region in the interlayer insulating layer in a thirddirection perpendicular to the first and second directions; a secondcontact plug connected to the gate structure through the interlayerinsulating layer, and overlapping at least one of the plurality ofactive fins in the third direction, an upper surface of the secondcontact plug being higher than an upper surface of the first contactplug; a first metal line disposed on the second interlayer insulatinglayer, and having a metal via directly connected to the first contactplug through the interlayer insulating layer, the metal via arranged ina diagonal direction with the second contact plug in a plan view; and asecond metal line disposed on the interlayer insulating layer, anddirectly connected to the second contact plug.
 2. The semiconductordevice of claim 1, wherein a length of the first contact plug in thesecond direction is larger than a length of the second contact plug inthe second direction.
 3. The semiconductor device of claim 1, wherein awidth of the first contact plug in the second direction is greater thana width of the metal via in the second direction.
 4. The semiconductordevice of claim 1, wherein a width of the first contact plug in thesecond direction is greater than a width of the first contact plug inthe first direction.
 5. The semiconductor device of claim 1, wherein thefirst metal line and the metal via are integrated with each other. 6.The semiconductor device of claim 1, wherein the interlayer insulatinglayer include a first interlayer insulating layer and a secondinterlayer insulating layer sequentially disposed on the gate structureand the source/drain region, and an etch stop layer disposed between thefirst interlayer insulating layer and the second interlayer insulatinglayer.
 7. The semiconductor device of claim 6, wherein an upper surfaceof the etch stop layer is higher than an upper surface of the firstcontact plug, and is lower than an upper surface of the second contactplug.
 8. The semiconductor device of claim 6, wherein the etch stoplayer comprises aluminum nitride (AlN).
 9. The semiconductor device ofclaim 1, wherein the first contact plug comprises a metal silicide layerconnected to the source/drain region.
 10. The semiconductor device ofclaim 1, wherein the first contact plug and the second contact plug eachcomprises tungsten (W), cobalt (Co), an alloy thereof, or a combinationthereof.
 11. The semiconductor device of claim 1, wherein each of thefirst contact plug and the second contact plug comprises a conductivebarrier layer disposed on lateral surfaces and a lower surface thereof.12. The semiconductor device of claim 1, wherein an interval between thefirst contact plug and the second contact plug is about 10 nm or less.13. The semiconductor device of claim 1, wherein the first metal lineand the second metal line each comprises copper (Cu) or acopper-containing alloy.
 14. A semiconductor device comprising: asubstrate having an active region; an active fin protruding from theactive region and extending in a first direction; a gate structuretraversing the active fin and extending in a second directionintersecting the first direction; a source/drain region disposed in theactive fin at a side of the gate structure; a first interlayerinsulating layer and a second interlayer insulating layer sequentiallydisposed on the gate structure and the source/drain region; an etch stoplayer disposed between the first interlayer insulating layer and thesecond interlayer insulating layer; a first contact plug extending fromthe source/drain region through the first interlayer insulating layer ina third direction perpendicular to the first and second directions; asecond contact plug connected to the gate structure through the firstinterlayer insulating layer, the etch stop layer and the secondinterlayer insulating layer, and overlapping a portion of the active finin the third direction; a first metal line disposed on the secondinterlayer insulating layer, and having a metal via directly connectedto the first contact plug through the second interlayer insulating layerand the etch stop layer; and a second metal line disposed on the secondinterlayer insulating layer, and directly connected to the secondcontact plug.
 15. The semiconductor device of claim 14, wherein theactive fin comprises a plurality of active fins arranged in the seconddirection, the source/drain region is disposed on adjacent active finsof the plurality of active fins, and the first contact plug is disposedon the source/drain region and extends in the second direction.
 16. Thesemiconductor device of claim 15, wherein the metal via is disposed on aportion of the first contact plug, and a width of the first contact plugin the second direction is greater than a width of the first contactplug in the first direction.
 17. The semiconductor device of claim 14,wherein an upper surface of the first contact plug is substantiallycoplanar with an upper surface of the first interlayer insulating layer.18. The semiconductor device of claim 14, wherein an upper surface ofthe second contact plug is substantially coplanar with an upper surfaceof the second interlayer insulating layer.
 19. A semiconductor devicecomprising: a substrate having an active region; a plurality of activefins protruding from the active region and extending in a firstdirection; a gate structure traversing the plurality of active fins andextending in a second direction intersecting the first direction; asource/drain region disposed in the plurality of active fins at a sideof the gate structure; a first interlayer insulating layer and a secondinterlayer insulating layer sequentially disposed on the gate structureand the source/drain region; a first contact plug extending from thesource/drain region through the first interlayer insulating layer in athird direction perpendicular to the first and second directions, andhaving an upper surface being substantially coplanar with an uppersurface of the first interlayer insulating layer; a second contact plugconnected to the gate structure through the first interlayer insulatinglayer and the second interlayer insulating layer, and overlapping atleast one of the plurality of active fins in the third direction, thesecond contact plug having an upper surface being substantially coplanarwith an upper surface of the second interlayer insulating layer; a firstmetal line disposed on the second interlayer insulating layer, andhaving a metal via directly connected to a portion of the first contactplug, the metal via arranged in a diagonal direction with the secondcontact plug in a plan view; and a second metal line disposed on thesecond interlayer insulating layer, and directly connected to the secondcontact plug through the second interlayer insulating layer.
 20. Thesemiconductor device of claim 19, wherein a width of the first contactplug in the second direction is greater than a width of the secondcontact plug in the second direction.